The present invention relates to computer desks, and more particularly to such a computer desk that uses a pneumatic cylinder and a sleeve on the pneumatic cylinder to support a desk top, and a tightening up screw to fix the sleeve at the desired elevation.
A variety of computer desks have been disclosed, and have appeared on the market. FIG. 1 shows a computer desk according to the prior art. This structure of computer desk comprises a base B shaped like an I-beam, a pneumatic cylinder A mounted on the base B on the middle, a desk top C supported on the pneumatic cylinder A and moved up and down with the piston rod of the pneumatic cylinder A to the desired elevation, and two upright guide tubes B1 and B2 bilaterally raised from the base B and inserted through a respective through hole at the desk top C to guide vertical movement of the desk top C. Because the piston rod of the pneumatic cylinder A is rotatable, the upright guide tubes B1 and B2 are necessary to prevent rotary motion of the desk top C upon reciprocating motion of the pneumatic cylinder A. If the piston rod of the pneumatic cylinder A is not rotatable, the upright guide tubes B1 and B2 can be eliminated.